Liquid cooling system for all-in-one computer

ABSTRACT

A desk-top type computer with a built-in LCD includes a chassis, a planar display attached to the chassis, a mother board attached to the chassis, heat generating portions including a CPU mounted on the mother board, and a memory device electrically connected to the mother board. A heat receiving head is fixed to at least one of the heat generating portions including the CPU, and the head is connected a tube filled with a cooling liquid. The tube is arranged in a serpentine or zigzag shape in a clearance between the chassis and the planar display facing the chassis. The cooling medium liquid circulating in the tube serves as a heat transferring medium to absorb the heat at the heat generating portion, and radiate the heat through the tube disposed in the clearance between the LCD and the chassis.

This is a continuation application of U.S. Ser. No. 09/795,122, filedJun. 18, 2001 now U.S. Pat. No. 6,519,146.

BACKGROUND OF THE INVENTION

The present invention relates to a desk-top type computer integrated orcombined with a liquid crystal display (LCD), or an all-in-one computer,and more particularly, to a liquid cooling technology for a heatgenerating elements in such a desk-top type computer.

A conventional art concerning a cooling system for electronic equipmentis such that a metal plate or heat pipe is interposed between heatgenerating elements and a metal cabinet wall in the electronic equipmentto thereby interconnect them thermally, thus radiating the heatgenerated by the heat generating elements through the metal cabinetwall.

Japanese Patent Application Laid-Open Publication No. H07-142886discloses a technology for liquid-cooling heat generating elements inelectronic equipment. It describes such a construction that the heatgenerated by semiconductor heat generating elements in the electronicequipment is received by a heat receiving head, a cooling medium liquidin which head is in turn transported through a flexible tube to a heatradiating head provided on a metal cabinet of a display unit to therebyradiate the heat generated by the semiconductor heat generating elementsthrough the heat radiating head via the cooling medium liquid from themetal cabinet effectively. The above-mentioned publication alsodiscloses an example of using a heat pipe as a heat transporting device,which has a construction that the heat generated by the semiconductordevices is transferred through a heat receiving metal plate to the heatpipe and then thermally connected to the other end of the heat pipedirectly attached to the wall surface of a metal cabinet, which servesas a heat radiating surface, to be radiated to the outside.

Further, Japanese Patent Application Laid-Open Publication No.H11-154036 discloses a heat dissipation technology for a desk-top typecomputer having an LCD unit. This publication specifically describesthat the air entered in a casing through an air inlet hole in a lowercasing section thereof, which surrounds the LCD, a mother board, etc.,is warmed by the heat from the mother board and a power source and thendischarged to the outside through heat radiating holes formed in the topand back surfaces of an upper casing section and in the top surface ofthe lower casing section. The publication further describes that acooling fan is provided at lower portion of the mother board to improvethe cooling efficiency.

In a desk-top type computer that typically comprises a body sectionhaving an LCD and a stand portion for rotatably supporting the bodysection, heat is generated by a CPU or MPU, etc. (hereinafter generallyreferred to as CPU) built in the body section, and the heat thusgenerated sometimes makes the operations of circuits unstable. It mayalso cause to thermal deformation of mechanisms. In particular, with anincrease in the operating frequency of the CPU in the recent years, thevalue of heat generated increases, and it has been desired toeffectively radiate the thus increased heat.

In the conventional art, there were discussions on the cooling by meansof a cooling medium liquid and that using a heat pipe for generalelectronic equipment. Concerning the cooling technologies for a desk-toptype computer integrated with an LCD, however, only some air coolingtechnologies have been suggested as is in Japanese Patent ApplicationLaid-Open Publication No. H11-154036. There have been no technologiesdisclosed presently of a cooling construction that is suited for thedesk-top type computer wit the built-in LCD.

It is conceivable to cope with an increase in the value of heatgenerated in the desk-top type computer by increasing the ventilationcapacity of a fan. This measure, however, may give rise to a problem ofnoise due to the blowing sound of the fan and another problem ofvibration during the operation of the computer. It is also conceivableto increase the heat radiation capacity by enlarging the size of an aircooling heat sink or heat radiating plate for radiating the heatgenerated by the heat generating elements such as a CPU. Thiscountermeasure is contradictory to the requirement for downsizing orminiaturization of the desk-top computer.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a cooling technology, whichis useful to be applied a desk-top type computer with an LCD unit, andto propose a novel construction for obtaining an appropriate heatradiating effect that is impossible with the prior art.

A display unit integral type computer, or an all-in-one computer,comprises a chassis, a plane-shaped display attached to the chassis, amother board attached to the chassis, a variety of electronic devicesand a CPU mounted on the mother board, and a memory device electricallyconnected to the mother board. A heat receiving head is fixed to atleast one heat generating portion including the CPU. A tube filled witha cooling medium liquid is connected to the heat receiving head, and thetube is secured onto the surface of the chassis, which is disposedopposite to the plane-shaped display with a clearance therefrom. Thecooling medium liquid circulating through the tube serves as a heattransferring medium to radiate the heat generated at the heat generatingportion through the tube on the chassis surface and the chassis itself.

Alternatively, the tube may be secured onto the back surface of theplane-shaped display, which is opposite to the chassis and attachedthereto with the clearance therefrom. The cooling medium liquidcirculating through the tube serves as a heat transferring medium, thusradiating the heat generated at the heat generating portion through thetube secured to the back surface of the plane-shaped display and theplane-shaped display itself.

Further alternatively, the tube may be led through the clearance betweenthe back surface of the plane-shaped display and the surface of thechassis and secured onto the back surface of the plane-shaped displayand onto the chassis surface. The cooling medium liquid circulatingthrough the tube serves as a heat transferring medium, thus radiatingthe heat generated at the heat generating portion through the tube onthe back surface of the plane-shaped display and the chassis surface,the chassis, and the plane-shaped display.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view showing an overall configuration for liquidcooling of a desktop type computer according to an embodiment of theinvention;

FIG. 2 is a front view of the overall configuration of FIG. 1 in which atube and a liquid receiver are fixed onto a main chassis;

FIG. 3 is a rear view of the overall configuration of FIG. 1 in which anassembly of a CPU and a heat receiving head, and a pump are disposed ona mother board;

FIG. 4 is a section view of another embodiment of the invention, inwhich a tube is secured to an LCD panel for heat radiation;

FIG. 5 is a section view showing a configuration example for preventingleakage of a cooling liquid in a desk-top type computer according tostill another embodiment of the invention;

FIGS. 6A and 6B are views illustrating configuration examples for liquidcooling and air cooling of a CPU according to the embodiment of theinvention;

FIGS. 7A, 7B, and 7C are views showing configuration examples concerningthe layout of a tube for liquid cooling in embodiments of the invention;

FIG. 8 is a section view showing another configuration exampleconcerning the layout of a tube for liquid cooling in an embodiment ofthe invention;

FIGS. 9A and 9B are section views showing configuration examplesconcerning the layout of a tube, a main chassis, and an LCD for liquidcooling according to embodiments of the invention;

FIG. 10 is a section view showing a configuration for liquid coolingaccording to an embodiment of the invention, in which fans exhaust heat;

FIGS. 11A, 11B and 11C are schematic diagrams showing the layout of apump, a heat receiving head, a tube and a liquid flowing direction;

FIG. 12 is a schematic diagram showing the function of a reservoir tankfor supplementing a cooling medium liquid and a function of removing airbubbles at the tube, heat radiation portion for liquid cooling accordingto the embodiment of the invention;

FIG. 13 is a section view of a configuration example for liquid coolingaccording to an embodiment of the invention, in which a tube and aliquid receiver are disposed on a rear cover; and

FIG. 14 is a section view of a configuration example for liquid coolingaccording to an embodiment of the invention, in which a tube is disposedon a main chassis facing a rear cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an overall configuration for liquid cooling of a desk-toptype computer according to an embodiment of the invention, FIG. 2 is afront view of the overall configuration of FIG. 1 in which a tube and aliquid receiver are fixed to a main chassis, and FIG. 3 is a rear viewof the overall configuration of FIG. 1, in which an assembly of a CPUand a heat receiving head, and a pump are disposed on a mother board.

As shown in FIGS. 1-3, the desk-top type computer comprises a computerbody 1 and a stand 2 for rotatably supporting the body 1, and in thecomputer body 1, a liquid crystal display (LCD) panel 5 is mounted onthe front side of a main chassis 3 and the mother board (a controlcircuit board) 4 is disposed on the back side thereof.

On the mother board 4 are arranged a variety of electric/electronicdevices, ICs, electronic circuits, etc. necessary for the operations ofthe computer as well as the CPU 9, power source circuits, and otherelements generating heat during the operation of the computer. On theback side of the LCD panel 5, i.e. on its side facing the main chassis 3are arranged a large number of connectors, and electric wiring lines,connected to the connectors, extend through an opening in the mainchassis 3 and are connected to terminals of the mother board 4. Thus, aspace is formed between the main chassis 3 and the LCD panel 5 forrouting the electric wiring lines etc.

Referring to FIG. 3, on the back side of the mother board, which isopposite to the main chassis side thereof, are arranged the CPU 9, thepower source circuits, a hard disk drive (HDD) 10, etc, which generateheat, and a heat receiving head 8 (see FIG. 1) is provided in contactwith the heat generating elements for transferring their heat to acooling medium liquid. Incidentally, the heat generating sources in thedesk-top type computer include, besides the CPU, a chip set, a displaycontroller, a power source portion, an HDD, an FDD, a CD-ROM portion, aCDR-R/W portion, and a DVD-ROM portion. The heat receiving head 8 ismade of a metal material having a high heat transfer rate and has itsinterior filled with a cooling medium liquid, which is thermallytransported to a heat radiating portion distanced from the heatreceiving head. Used as the cooling medium liquid is water or ethyleneglycol, but it is not limited to them. The cooling medium liquid ispressured by a pump 7 shown in the figure to collect heat at the heatreceiving head 8 while it is being circulated through a tube 6.

Although the tube 6 for transporting the cooling medium liquid istypically made of copper with a good heat transfer rate and a corrosionresistance, any other material may be used as far as they have theabove-mentioned properties. For example, a flexible tube made of asilicon-based compound can be employed because it has those properties.As will be described later, in particular such a tube as shown in FIGS.13 and 14 is routed in the same manner as a cable, and therefore aflexible tube may be used as a portion other than those fixed to thecover or the chassis. For instance, part of the path requiringflexibility may be made by a flexible tube of silicon-based compound inplace of a copper tube.

The tube 6 for transporting the cooling medium liquid goes through theheat receiving head 8, the pump 7, and the opening in the main chassisup to the front side of the main chassis (see FIG. 2), i.e. up to thespace between the main chassis 3 and the LCD panel 5, and is fixed tothe main chassis front side by screwing, bury-in, or any otherappropriate fixing method, thus forming a heat radiating portion. It isto be noted here that the place where the tube is disposed on the frontside of the main chassis is the space originally provided for, asdescribed above, arranging the electric wiring lines etc. of the LCDpanel, that is, it utilizes the existing space and is not a newly addedspace for arranging the tube piping on the front side of the mainchassis 3. Thus, this is not adverse to the requirement for thinning andminiaturization of the entire equipment.

As shown in FIG. 2, the tube 6 is secured on the front side of the mainchassis, while being arranged spirally or in a zigzag or serpentinemanner. With this construction, the heat generated by the CPU etc. andtransferred to the cooling medium liquid is effectively transferred tothe main chassis 3 through the copper tube. The main chassis isoriginally for forming an overall computer framework that is coupledwith the stand 2, and it has a considerably large area in total and ismade of a metal material. Accordingly, all the area of the front andrear sides of the chassis can be used for external heat radiation, thusachieving a high efficiency heat radiation.

Referring to FIG. 2 again, the tube 6 fixed, for example, spirally, onthe front surface of the main chassis 3 has a possibility that thecooling medium liquid will leak at the joints of its flexion or bendingportions due to thermal shrinkage thereof. To prevent the thus leakedcooling medium liquid from flowing along the main chassis down to thestand, a liquid receiver 11 for collecting that cooling medium liquid isprovided at the lower part on the front side of the main chassis. Themain chassis is usually kept in an upright state or a state slightlyinclined with respect to the upright state, and the leaked liquid flowsdownward along the surface of the main chassis and can be collected inthe liquid receiver 11. Although FIG. 2 shows the example where theliquid receiver 11 is disposed on the front surface side of the mainchassis 3, another liquid receiver may be provided on the back side tocollect the leakage liquid coming down along the tube.

Further, a cover 12 is provided for covering the whole of the computerbody 1. A portion of the cover 12 that corresponds to the lower portionof the space between the LCD panel 5 and the main chassis 3 is formedwith an air inlet 13 for air-cooling the heat radiating portion thatcomprises the heat transporting tube and the main chassis. Similarly,the upper portion of the cover 12 is also formed with an air outlet 14for exhausting air. An air flow-through path from the air inlet 13 tothe air outlet 14 has a chimney effect for air to effect a furtherair-cooling on the heat generating portion, thus improving the coolingefficiency.

In a modification of the first embodiment of the invention describedabove, an air ventilating fan is provided at the lower portion in thecover to forcedly take in air for heat exchange at the heat generatingportion and then exhaust the air, thus further improving the coolingefficiency.

As mentioned above, according to the first embodiment of the invention,the casing (or cover) of a currently used desk-top type computer can beused as it is without changing its size. Further, a large surface areaof both the front and back sides of the main chassis can be utilized inradiation of heat to achieve an even more improved heat radiationeffect. Furthermore, the chimney effect of air at the heat radiatingportion of the tube is expected to further improve the heat radiationeffect.

FIG. 4 now shows a configuration example for liquid cooling of adesk-top type computer according to another embodiment of the invention.As shown in FIG. 4, this embodiment is so constructed that a tube goesthrough a pump, a heat receiving head, and an opening in a main chassisand is fixed on the back surface of an LCD panel to form a heatradiating portion. The back surface of the LCD panel is made of a metalmaterial, and the heat of a cooling medium liquid from the tube, whichis arranged spirally or in a zigzag or serpentine manner, can betransferred effectively onto the back surface of the LCD panel andradiated.

A space between the LCD panel and the main chassis is utilized forarranging electric wiring lines etc., which are connected with theconnectors of the LCD panel in the same manner as described with theembodiment shown in FIG. 1. Accordingly, no additional space is requiredfor arranging the tube on the back surface of the LCD panel to form theheat radiating portion. Also in the embodiment shown in FIG. 4, the heatradiating portion can be provided without changing the externaldimensions of the currently-used casing of a desk-top type computer,thus contributing the thinning and miniaturization of the computer.

Furthermore, the back side of the LCD panel has a large area of themetal surface, and heat dissipation can be carried out at highefficiency while utilizing this large area. In addition, the provisionof the air inlet in the lower portion of and the air outlet in the upperportion of the cover, which covers the clearance between the LCD paneland the main chassis, form in combination an air flow-through path fromthe air inlet at the lower part to the air outlet at the upper portion,and an improvement of the heat radiating effect is expected due to theso-called chimney effect.

FIG. 10 shows a modification of the air flowing to the heat radiatingportion in the embodiment of FIG. 1, in which an air ventilating fan isprovided at the lower portion or the upper portion of the cover, whichcovers the clearance between the LCD panel and the main chassis, or fansare provided at both the upper and the lower portion of the cover,respectively. The provision of the fans shown in FIG. 10 can furtherexpedite the movement of air. Further, the provision of the fans enablesthe transportation of a large volume of cooling air. This allows the airinlet and outlet openings in the lower and upper portions to benarrowed, thus causing an effect of thinning the apparatus andsuppressing the entry of dust and dirt.

FIG. 5 now shows a configuration for prevention of liquid leakage in theliquid cooling of a desktop type computer according to an embodiment ofthe invention. This embodiment takes a countermeasure for a case wherecooling medium liquid leaks at a heat radiating portion in such anarrangement that the heat from a heat receiving head is radiated on thefront side of a main chassis as described with the embodiment shown inFIG. 1. In the desk-top type computer with an LCD, which comprises acomputer body and a stand, the body is supported by the stand in anupright state or a state slightly inclined from the upright state bothin use and not in use, so that the liquid leaking from the heatradiating portion, which relatively tends to cause liquid leakage in theliquid cooling apparatus, flows down to the lowest portion of the mainchassis because of the above-mentioned inclination state of the computerbody. Accordingly, this embodiment features providing a liquid receiverat the lowest portion of the main chassis.

As can be seen from FIG. 5, the liquid leaking from the heat radiatingportion flows downward along the front side surface of the main chassisand is collected by the liquid receiver at the lowest portion of themain chassis. The liquid receiver may be removably attached at thelowest portion of the main chassis in FIG. 5, or it may be formed in oneunited body with the main chassis. Furthermore, in the configurationexample shown in FIG. 5, the liquid receiver is integrated with thecover for collecting the liquid coming downward along the surface of themain chassis.

Furthermore, as the connections or coupling portions of the coolingmedium liquid tube are supported to be liable to cause liquid leakage, aliquid receiver may be provided on the back side of the main chassis toreceive the liquid leaking from the heat receiving head and the pump.This is because the liquid leaking from that connecting portions of thetube will flow down along the external surface of the tube downward andthe back side surface of the main chassis. In addition, to receive theliquid dropping from the lowest portion of the mother board on which thepump or the heat receiving head is mounted, a liquid receiver may beintegrated with the cover at a position corresponding to the lowestportion of the mother board. Further, a liquid receiver may be providedon a portion of the stand close to the computer body.

As described above, the embodiments shown in FIGS. 1 and 5 can collectthe leaked cooling medium liquid and also prevent it from damaging thedevices within the stand.

FIGS. 6A, B now show configurations for liquid cooling and air coolingin a desk-top type computer according to another embodiment of theinvention. The embodiment concerning the configurations shown in FIGS.6A, B has such a construction that a heat receiving head is fixed to aCPU arranged on a mother board to thereby receive the heat generated bythe CPU in order to transfer the generated heat via a cooling mediumliquid (water or ethylene glycol) in a tube to a heat radiating portionon the front side of a main chassis or the back side of an LCD panelsimilarly to the embodiment shown in FIGS. 1 and 4 and that a heatradiating fin is provided on the heat receiving head.

More specifically, the embodiment shown in FIG. 6 aims at radiating byliquid cooling an extra heat that cannot be radiated from the heatradiating fin provided on the heat receiving head. Since the desk-toptype computer has an extra space between the back side of the motherboard and the rear cover, such a heat radiating fin as provided in thisembodiment does not lead to an extra change in the external sizes. FIG.6B shows a construction in which a fan is further provided on the heatradiating fin on the heat receiving head. The provision of theventilating fan realizes the effective and rapid radiation of heat fromthe heat radiating fin.

As mentioned above, the embodiment shown in FIG. 6 applies liquidcooling and air cooling in combination to the heat generating sourcesuch as the CPU, and it is possible to increase the maximum capacity ofheat radiation and improve the heat radiation efficiency. Furthermore,the embodiment has an advantage that, even when an abnormal situation inthe liquid cooling system such as freezing of the cooling medium liquidsuch as water, the air cooling effect by the heat radiating fin securedto the heat receiving head allows the computer to be operatedcontinuously.

FIGS. 7, 8 and 9 show configuration examples concerning the shape andconstruction of a heat radiating portion in a tube. FIG. 7A is a sectionview of the configuration in which a spiral tube for heat radiation isdisposed between an LCD panel and a main chassis, FIG. 7B is a plan viewof the configuration of FIG. 7A as viewed from above, and FIG. 7C is asection view of the other configuration, in which a spiral tube isdisposed between an LCD panel and a main chassis and a pipe made ofaluminum etc. is disposed at the center of the tube for heat radiation.The examples shown in FIG. 7 employ such a construction that the tube,extending from a heat receiving head through an opening in a mainchassis, is led to the back side of the LCD panel and arranged alongthis back side, and is then led to the main chassis side and arrangedalong the surface of the main chassis (the arranging order may bereversed), thus forming the heat radiating portion. In thisconstruction, both the LCD panel and the main chassis can serve as heatradiating surfaces, and further improvement of the heat radiationefficiency can be expected. The construction shown in FIG. 7C aims atfurther improving the heat radiation efficiency by arranging orattaching the heat radiating metal of aluminum etc. in the central spaceof the spiral tube disposed over the LCD panel and the main chassis.

FIG. 8 shows a configuration example that a spiral tube is arrangedbetween a mother board, on which heat generating elements are mounted,and a rear cover and, in the central space surrounded by this spiraltube, a barrel-shaped heat radiating metal such as aluminum is arrangedfor heat radiation. In the examples of FIG. 8, openings for airventilation are formed as an air inlet and an air outlet in portions ofthe cover corresponding to the upper and lower portions of thebarrel-shaped metal. Then, with a hollow structure of this barrel-shapedmetal, an air path is formed which extends from the air inlet throughthe interior of the hollow body to the air outlet, and the heattransferred from the tube to the barrel-shaped metal is effectivelyradiated thanks to the chimney effect.

FIG. 9A is a view of the example in which a tube is arranged between anLCD panel and a main chassis with no contact and no fixation thereto,and FIG. 9B is a view showing a distance between an LCD panel and a mainchassis, which is almost equal to the diameter of a tube, and the tubecontacting over its entire length with the LCD panel and the mainchassis for heat radiation.

FIG. 11 shows the relationship between a flow direction of a coolingmedium liquid and a heat radiating system, which comprises a pump forsupplying the cooling medium liquid, a heat receiving head (a waterjacket W/J), a tube, and a tube heat-radiating portion formed in aspiral shape or in a zigzag or serpentine shape. In FIG. 11A, the liquidflows in the direction illustrated, and the flow path from the pumpthrough the heat radiating portion up to the top portion is long.Accordingly, although the pump capacity has to be enlarged by that much,air bubbles, which will occur in the cooling medium liquid in the tubeincluding the heat radiating portion, escape upward along the flow, thusenhancing the effect of removing air bubbles. To this end, an air-bubbleremoving opening is provided at the top portion. In FIG. 11B, since theliquid flows in the direction illustrated, the flow path from the pumpto the top portion is short as compared with that of FIG. 11A, and thepump can be reduced in capacity. Further, FIG. 11C shows the situationthat, since there are a plurality of heat generating elements besidesthe CPU as heat generating sources in the desk-top type computer asdescribed above, a plurality of heat receiving heads providedcorresponding to the plurality of heat generating elements are thermallyconnected in series through the tube.

FIG. 12 is a schematic diagram showing the function of a reservoir tankfor supplementing the cooling medium liquid and the function of removingair bubbles in the tube heat radiating portion. As shown in FIG. 12, thereservoir tank for the liquid is provided at the highest portion in thecirculating path of the cooling medium liquid, i.e., the top of thespiral tube structure or the heat radiating portion, and the liquid inthe reservoir tank serves as a supplementary liquid when the coolingliquid leaks from the tube or is evaporated. In addition, thedisposition of the reservoir tank at the highest portion of the liquidcirculating path causes air bubbles generated in the circulating path tomove into the above-mentioned tank.

FIG. 12 also shows the tube heat radiating portion having such a shapethat the tube is folded not to simply extend horizontally but in amanner that it goes from one turning point along a path with aninclination angle of a to another turning point. The liquid circulatingpath is thus inclined at the heat radiating portion to cause air bubblesgenerated in the cooling medium liquid at the heat radiating portion toeasily escape into the reservoir tank. That is, this makes it possibleto rapidly eliminate through the reservoir tank air bubbles in thecooling medium liquid, which would occur due to some liquid leakage.

FIG. 13 now shows another configuration example for liquid cooling in adesk-top type computer according to an embodiment of the invention. Inthis embodiment, the heat radiating portion of a cooling medium liquidtube is formed on a back cover or rear cover provided on the back sideof a body, and the back cover is typically made of metal or plastic, sothat heat may be radiated to the outside from the heat radiating portionthrough the back cover of a large surface area. The plastic material ofthe back cover has almost the same heat radiation properties as those ofmetal. FIG. 13 also shows a construction that a liquid receiver forcollecting a leakage liquid of the cooling medium is provided under thetube heat radiating portion disposed on the back cover.

For maintenance and inspection of the computer which is done typicallyby removing the back cover to inspect a variety of devices within thebody, this embodiment employs a hinge construction by which the backcover can be opened and closed rather than being removed. Alternatively,a construction may be such that the heat radiating portion is providedon the back cover fixed to the body, and when maintenance andinspection, an LCD panel is pushed down forward with its bottom side asa rotary supporting point and then opened with its side as a rotarysupporting point for inspection of the internal devices.

FIG. 14 shows further another configuration example for liquid coolingin a desk-top type computer according to an embodiment of the invention.In this embodiment, as viewed from the front side of the computer, anLCD panel, a mother board, a main chassis, a heat radiating portion, anda back cover are arranged in this order. It has a construction that theback cover can be detached from the body, the main chassis is disposedopposite to the back cover, and the heat radiating portion is attachedto the main chassis, in which heat is transferred to the back coverthrough a heat conductor having an elasticity function, which isprovided between the heat radiating portion and the back cover. That is,through the elastic heat conductor, the heat radiating portion buttsagainst the back cover with no gap, thus providing a good heat radiatingeffect.

This embodiment enables heat to be radiated through the back cover of alarge heat radiation area and an error in mounting of the back cover tobe accommodated by means of the elastic heat conductor.

According to the invention, it is possible to effectively radiate to theoutside the heat generated by hot heat generating elements such as a CPUin a desk-top type computer comprising an LCD.

What is claimed is:
 1. An all-in-one computer comprising: a CPU; adisplay; a cooling liquid circulation means comprising a tubular flowpath filled with a cooling liquid, a part of said tubular flow pathbeing disposed on a back face of the display; a cooling liquid pumpconnected with the cooling liquid circulation means for circulating thecooling liquid in one direction; a CPU cooling section connected to amiddle portion of the cooling liquid circulation means and cooling theCPU with the cooling liquid; and a reserve tank having an air space anda cooling liquid space at a vertically highest portion of the coolingliquid circulation means.
 2. An all-in-one computer according to claim1, wherein said air space of the reserve tank collects air bubbles inthe cooling liquid circulation means, and said cooling liquid space isfilled with supplementary cooling liquid.
 3. An all-in-one computercomprising: a CPU; a display; a cooling liquid circulation meanscomprising a tubular flow path filled with a cooling liquid, a part ofsaid tubular flow path being disposed on a back face of the display; acooling liquid pump connected with the cooling liquid circulation meansfor circulating the cooling liquid in one direction; and a CPU coolingsection connected to a middle portion of the cooling liquid circulationmeans and cooling the CPU with the cooling liquid, said CPU coolingsection comprising a heat receiving head transferring heat generated bythe CPU to the cooling liquid and a heat radiation fin radiating theheat from the heat receiving head, so that the generated heat of the CPUis thermally transferred through the cooling liquid circulation meansand is released from the heat radiation fin to atmosphere; a reservoirtank connected to the cooling liquid circulation means at a positionabove the cooling liquid pump for eliminating air bubbles in the coolingmedium liquid.
 4. An all-in-one computer according to claim 3, whereinsaid CPU cooling section further comprises a cooling fan and cools theheat radiation fin by said cooling fan.
 5. An all-in-one computeraccording to claim 4, wherein said CPU cooling section has a three-layerstructure in which the heat receiving head is mounted on an uppersurface of the CPU, the heat radiation fin is attached to an uppersurface of the heat receiving head and the cooling fan is mounted on anupper surface of the heat radiation fin.
 6. An all-in-one computeraccording to claim 4, wherein a part of the generated heat of the CPU istransferred to the cooling liquid at the heat receiving head, and aremainder of the heat is forcedly air-cooled at the heat radiation finby the cooling fan.
 7. An all-in-one computer according to claim 4,wherein the generated heat of the CPU is radiated from the heatradiation fin during a normal operation of the computer, and when theheat has a higher temperature, is partially released from the heatradiation fin and is thermally transferred through the cooling liquidcirculation means to be radiated.
 8. A CPU cooling unit for anall-in-one computer having a CPU, a display, cooling liquid circulationmeans comprising a tubular flow path filled with a cooling liquid, apart of the tubular flow path being disposed on a back face of thedisplay, and a cooling liquid pump connected with the cooling liquidcirculation means for circulating the cooling liquid in one direction,said CPU cooling unit comprising: a heat receiving head connected to amiddle portion of the cooling liquid circulation means and transferringheat generated by the CPU to the cooling liquid; and a heat radiationfin releasing heat stored in the heat receiving head to atmosphere; theCPU cooling unit being disposed below a reservoir tank connected to thecooling liquid circulation means for eliminating air bubbles in thecooling liquid.
 9. A CPU cooling unit according to claim 8, wherein saidheat receiving head is disposed on a thermally connecting face side tothe CPU, and said heat radiation fin is provided on an opposite side toa thermally connecting face to the CPU.
 10. A CPU cooling unit for anall-in-one computer having a CPU, a display, a cooling liquidcirculation means comprising a tubular flow path filled with a coolingliquid, a part of the tubular flow path being disposed on a back face ofthe display, and a cooling liquid pump connected with the cooling liquidcirculation means for circulating the cooling liquid in one direction,said CPU cooling unit comprising: a heat receiving head connected to amiddle portion of the cooling liquid circulation means and transferringheat generated by the CPU to the cooling liquid; and a heat radiationfin subjected to forced radiation of heat stored in said heat receivinghead to atmosphere; the CPU cooling unit being disposed below areservoir tank connected to the cooling liquid circulation means foreliminating air bubbles in the cooling liquid.
 11. A CPU cooling unitaccording to claim 10, wherein said heat receiving head is disposed on athermally connecting face side to the CPU, and said heat radiation finsubjected to forced heat-radiation is provided on an opposite side to athermally connecting face to the CPU.